Precise measurement of the W-boson mass with the Collider Detector at Fermilab

We present a measurement of the W -boson mass, M W , using data corresponding to 2.2     fb − 1 of integrated luminosity collected in p ¯ p collisions at √ s = 1.96     TeV with the CDF II detector at the Fermilab Tevatron. The selected sample of 470 126 W → e ν candidates and 624 708 W → μ ν candidates yields the measurement M W = 80 387 ± 12 ( stat ) ± 15 ( syst ) = 80 387 ± 19     MeV / c 2 . This is the most precise single measurement of the W -boson mass to date.